1. Field of the Invention
This invention relates to an assembly for sealing the open end of a pipe. More specifically, the invention relates to a well cap assembly for sealing the top end of a well casing, which is used to extract a fluid from the ground.
While the assembly of the present invention was designed to seal the top end of a well casing at a landfill site, it will be appreciated that the assembly can be used on other pipes or conduits such as the casings of oil or gas wells.
It has been found that when well casings are being installed at a well site it is not uncommon for the top end of the casing to be out somewhat less than perpendicular the longitudinal axis of the casing, i.e. the casing is not cut ‘square’. Moreover, a casing is often not perfectly round. Accordingly, caps and gasket on the top end of the pipe do not always provide a good seal, permitting the unintentional escape of well fluids (gases and/or liquids) from the well or, when the well is under vacuum, allowing the ingress of fluids into the well.
2. Description of the Related Art
A literature search discloses a variety of pipe seals including those described in U.S. Pat. No. 3,494,504, issued to J. C. Jackson on Feb. 10, 1970; U.S. Pat. No. 3,667,640, issued to Joseph. G. Morrow on Jun. 6, 1972; U.S. Pat. No. 3,901,167, issued to Dale C. Reese on Aug. 26, 1975; U.S. Pat. No. 4,175,671 issued to Harold H. Holl et al on Nov. 27, 1979; U.S. Pat. No. 4,303,101, issued to James W. Tholen on Dec. 1, 1981; U.S. Pat. No. 4,415,005, issued to Harlo W. Jahzen on Nov. 15, 1983; U.S. Pat. No. 4,493,344, issued to Allen D. Mathison et al on Jan. 15, 1985; U.S. Pat. No. 4,848,458, issued to Thomas S. Holdsworth et al on Jul. 18, 1989; U.S. Pat. No. 5,437,309, issued to Robert D. Timmons on Aug. 1, 1995; and U.S. Pat. No. 7,464,727, issued to Richard E. Larson et al on Dec. 16, 2008. Many of the patented devices include molded elements which would result in high production costs. Others of the devices would not provide a solution to the problem described above.